It is beyond question that the Internet has had an enormous impact on societies, businesses and individuals throughout the world. As a worldwide, publicly accessible network of interconnected computer networks, the Internet has enabled a large proportion of the world's population to gain access to vast amounts of information, to communicate via e-mail and file transfers and online chat rooms, and to complete any number of business activities and commercial transactions. With remote access to data processing systems, collaborative working, file sharing and voice-over-IP (VoIP) communication, the Internet has avoided the need for a great deal of business-related travel and achieved huge improvements in education and productivity.
Many innovators believe that future advances in Internet use will be dominated by immersive, computer-simulated, three-dimensional (3D) environments that can simulate spaces within the external world. Such environments are referred to herein as ‘virtual worlds’ (but are also known in the art as a ‘metaverse’, following Neal Stephenson's science fiction novel “Snow Crash”, 1992, Bantam Books, USA). In a virtual world, computer users interact with each other, and with objects, via ‘avatars’ which are representations of a character that the user has associated with himself or herself. In an immersive 3D virtual world, avatars tend to be three-dimensional graphical representations of people (often stylized rather than an accurate representation of the user); but an avatar within an Internet forum may be a two dimensional (2D) image or icon. The terms ‘avatar’ and ‘virtual world’ as used herein are intended to encompass 2D icons in a two-dimensional virtual environment such as a conventional Internet application using the World Wide Web (e.g. a virtual shopping mall) as well as to refer to 3D representations of a user-associated character in an immersive, computer-simulated 3D environment.
In many 2D and 3D interactive computer games, it is well known for avatars to interact with each other and with their surroundings. In Second Life (an example Internet-based virtual world developed by Linden Research, Inc. (“Linden Lab”) with contributions from its user community or “Residents”), users can simulate conversations between their avatars using text-based communication. This includes instant messaging for private conversations, and localized public broadcasts of text between avatars that are within a certain distance from one another. In virtual worlds such as Second Life, when an avatar comes into simulated physical contact with another avatar or a non-avatar virtual object, the computer that is simulating their environment applies a set of algorithms to simulate the effects of that contact; taking account of factors such as simulated gravity, conservation of momentum, conservation of energy, etc.
An avatar's field of view is also repeatedly recalculated as the avatar moves within the virtual world, and the avatar's field of view (or a cropped portion of it) is presented to the user via an image on a display screen. When an avatar moves within a massively multiplayer online role-paying game (MMORPG), many other avatars and non-avatar virtual objects will typically come within their field of view. An avatar-controlling user will choose to interact with some of these other avatars and non-avatar virtual objects, and will disregard others.
In many cases, it is sufficient to detect simulated physical contacts with other avatars and objects (when rules for calculating simulated physical effects need to be applied) and to allow the user to initiate communications and to respond to other avatars' attempts to communicate. Users can be left to decide and to remember which avatars and other objects they considered interesting but perhaps chose not to interact with. For example, a user may have chosen to avoid a simulated physical interaction, or chosen not to participate in a communication, and then the only record of the user's interest is in the user's memory. Many satisfactory computer games respond to simulated physical interaction events and leave the user to control other types of interaction.